Thanks everyone for your feedback.
I found the problem. I took the back cabinet plate off behind the entertainment system and did some wire tracing (yes, tonnes of wires). What I found was that the antenna wire came to the back side of one of the male coax jacks on the power booster wall plate and that the TV distribution splitter input came from the other male coax jack off the same wall plate (you got it, no connection between them). So I put a jumper on the two jacks and there was the picture.
Sure would have been nice to know at the beginning. Again I'm not sure why there isn't any wiring diagrams or instructions on what the wall plate jacks inside and outside the trailer are and how to use them.
On another note, the second thing I did following the channel scan and review of my available air channel feeds (4 located, 1 pretty clear, 3 not so much) was I went up on the roof with the "Jack" antenna upgrade and did the two minute switch. I quickly removed the 2 snap rings off the mounting pins below the head of the existing winegard antenna, pulled the two pins, unscrewed the coaxial cable and removed the winegard antenna. I then mounted the bracket that comes with the new antenna to the head of the new antenna underside, 4 screws. I then placed the head of the new "Jack" antenna over the existing two square tube antenna mounting arms (nose of the "Jack" facing the direction of the pointing dial in the trailer) and lined up and inserted the two mounting pins I had removed earlier, snapped the rings back on and did up the coax (after putting the water proofing gel and boot cover over the coax connector, not manditory but recommended).
I went down, pointed the antenna, turned on the power booster (didn't need the one that came with the new antenna) and did a new channel scan. I picked up 2 additional channels and all came in digital high definition. Wow!!!!! All that have had a look at the campgroind are really impressed, they thought I had satelite TV and one guy said he is considering it for at home!!!!
So things are good and it all worked out.
Thanks again for sharing in this post.